Selectable tap outlet flow adjuster

ABSTRACT

The present invention relates to a selectable tap outlet flow adjustor that is designed to change the water flow from a water tap/faucet to run or spray. The device includes a control disk for selecting the flow state comprising angularly spaced open voids spaced about an axis through which water passes when in use and a spray forming disk. The spray forming disk has angularly spaced open running voids spaced about an axis through which water may pass when in use and perforations in those parts of its body between the angularly spaced open voids through which water may pass at a reduced spray rate when in use. The spray forming disk and control disk are axially rotatable with respect to each other whereby the open running voids of the spray forming disk may be aligned with the open voids in the control disk.

FIELD OF THE INVENTION

The present invention concerns selectable tap flow adjusting appliances of the type that are fitted to the outlet/delivery end of a tap (faucet) and which enable the user to select between water delivery flow patterns.

BACKGROUND TO THE INVENTION

Selectable tap outlet flow adjustors of the type in question have been available for many decades but in recent years their value as a means of economizing on water usage has become increasingly important. Many of the currently available tap outlet flow adjustors are designed primarily to provide selection between aerated and non-aerated water flows. In aerated flow state air is bubbled in with the water, reducing the amount of water used but allowing a soft bubbly flow. A common aspect of the design of these devices is that they tend to be arranged with the different flow states achieved by switching between an inner central/axial flow path and an eccentric or outer concentric flow path and are generally relatively bulky, spreading laterally and extending well beyond the delivery end of the tap. Examples of this are shown in U.S. Pat. No. 4,221,338 and applications US 20060163387 and US 20070235091. Another type of such device is the non-aerated flow-reduced design that in its spray state forces the water through a set of smaller holes in the tap head, producing a fine, firmer spray. Again it is common in these tap heads to arrange the finer holes concentric to a broad inner central/axial flow path.

In all of these existing tap outlet flow adjustor designs the structure is generally not only obtrusive but their assembly also tends to be liable to lime-scale obstruction over time in areas with hard water. Many tend to seize up, becoming increasingly difficult to move between operative states.

It is amongst the general objects of the present invention to provide a new selectable tap outlet flow adjustor that addresses these problems of the existing tap outlet flow adjustor designs, providing a device that is affordable, economic in its use of water, discrete in form and attractive, able to maximize space between the tap outlet/delivery end and the basin or object to be cleaned and is relatively easy to operate and maintain in good functional condition, even in areas with hard water.

It is a further object to provide a selectable tap outlet flow adjustor that is suited for use in kitchen sinks, washing basins or the like to be able to, for example, facilitate dish washing/cleaning tasks and be able to select between focused and spread area coverage as required to improve efficiency of washing/cleaning and thereby save on cleaning time and overall water usage.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a selectable tap outlet flow adjustor for controlling water flow, the flow adjustor comprising:

-   -   a control disk for selecting the flow state comprising angularly         spaced open voids spaced about an axis through which voids water         passes when in use; and     -   a spray forming disk, the spray forming disk also comprising         angularly spaced open running voids spaced about an axis through         which voids water may pass when in use but further comprising         perforations in those parts of its body between the angularly         spaced open voids through which perforations water may pass at a         reduced spray rate when in use, the spray forming disk and         control disk being axially rotatable with respect to each other         whereby when one disk is rotated relative to the other so that         the open running voids of the spray forming disk are aligned         with the open voids in the control disk, water may pass through         at a first flow rate and when one disk is rotated relative to         the other so that the perforations in the spray forming disk are         aligned with the open voids in the control disk, water may pass         through at a second flow rate, less than the first flow rate and         as a spray.

For the purposes of the present invention the term disk is intended to embrace substantially flat, substantially circular plate-like structures but the disk need not be entirely flat and may be convex or concave and in embodiments the discs may have an upstanding circumferential annular wall and/or central lug and have much of the area of their major surface removed as the voids.

Particularly preferably the open voids of the control disk and the open running voids of the spray forming disk are sectors of the respective disks.

The selectable tap head suitably comprises a body mountable to the delivery end of a tap and preferably the body is a short cylinder in form that preferably is adapted to be inserted into the delivery end of a tap. It preferably has an external screw thread to be fastened to a tap end that has an internal screw thread though other mounting arrangements may be used for different types of tap end. For some tap ends a clamping type of arrangement may be required.

Preferably the body and the spray forming disk are unitary/integrally formed or integrally assembled. This arrangement is preferable to the body and the control disk being unitary/integrally formed or integrally assembled since it allows for easier assembly and maintenance. Alternatively the body may comprise a separate holding disk that holds the control disk so that the control disk does not rotate with respect to the holding disk.

The selectable tap head is suitably configured to match with existing/standard taps and to meet local government regulations to control the water flow pattern. With this compact and discrete device fitted to the delivery end of a tap users can consume water with greater control and convenience and also economise on their use of water.

The device allows a user to select a first flow state where the water flows in a stream or jet suitable for, for example, filling up a vessel such as a kettle or for localised/focussed cleaning of items. In this state the water flows rapidly through a set of large angularly spaced voids/apertures of the device and which can save time for filling up work.

In order to perform other tasks where the flow rate of the first flow state may be unnecessary and a lower flow rate with a broader spray pattern of delivery may be more appropriate (for example, for more general spray washing of dishes and pans) a second flow state may be selected on the tap head by turning the control disk or the spray-forming disk about its axis to bring the perforated plate sectors of the spray-forming disk into register with the void sectors of the control disk.

The perforations are preferably directed/slanted laterally/radially outwardly so that the spray has a broad spread and not simply oriented parallel to the axis of the tap outlet. The passageway that each perforation forms may be so slanted and/or particularly preferably the perforations each terminate at their external end in a respective nozzle that is directed/slanted laterally/radially outwardly.

In this second flow state the water can be sprayed over a relatively wide area even when the supplied water pressure is low. This spray over a wider area rather than just running on one spot/area enables economisation on use of water (and of money where water supply is metered). The tap head is not designed to aerate the water and it does not allow air or any counter-flow against the water flow direction.

The device of the present invention may be made to a range of dimensions to suit existing/standard commercially available taps and may be sold with taps or separately to be fitted to the outlet of the tap/faucet by the user.

According to a second aspect of the present invention there is provided a selectable tap outlet flow adjustor for controlling water flow, the flow adjustor being mountable to the outlet/delivery end of a tap and comprising:

-   -   a control disk for selecting the flow state comprising open         voids through which voids water passes when in use; and a spray         forming disk, the spray forming disk also comprising open         running voids through which voids water may pass when in use but         further comprising perforations in those parts of its body         between the open voids through which perforations water may pass         at a reduced spray rate when in use, the spray forming disk and         control disk being axially rotatable with respect to each other         whereby when one disk is rotated relative to the other so that         the open running voids of the spray forming disk are aligned         with the open voids in the control disk, water may pass through         at a first flow rate and when one disk is rotated relative to         the other so that the perforations in the spray forming disk are         aligned with the open voids in the control disk, water may pass         through at a second flow rate, less than the first flow rate and         as a spray wherein at least some of the perforations have their         flow output directed/slanted laterally/radially outwardly so         that the spray has a broadened spread.

According to a third aspect of the present invention there is provided a selectable tap outlet flow adjustor for controlling water flow, the flow adjustor being mountable to the outlet/delivery end of a tap and comprising:

-   -   a control disk for selecting the flow state comprising open         voids through which voids water passes when in use; and a spray         forming disk, the spray forming disk also comprising open         running voids through which voids water may pass when in use but         further comprising perforations in those parts of its body         between the open voids through which perforations water may pass         at a reduced spray rate when in use, the spray forming disk and         control disk being axially rotatable with respect to each other         whereby when one disk is rotated relative to the other so that         the open running voids of the spray forming disk are aligned         with the open voids in the control disk, water may pass through         at a first flow rate and when one disk is rotated relative to         the other so that the perforations in the spray forming disk are         aligned with the open voids in the control disk, water may pass         through at a second flow rate, less than the first flow rate and         as a spray wherein a resilient biasing means is provided in the         device to bias the device to the first or second state.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be further described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is an exploded general assembly diagram of a first preferred embodiment of the tap outlet flow adjustor having a control disk for selecting the flow state and a spray forming disk, the spray forming disk being cylindrical and adapted to fit to the outlet/delivery end of a tap by an external screw thread on the spray-forming disk;

FIG. 2 comprises a set of views of the spray-forming disk showing its front and rear faces and details of the faces;

FIG. 3 comprises a set of views of the control disk showing its front and rear faces and details of the faces;

FIG. 4 comprises a set of three views each of each of the biasing spring, the washer, the control disk and the spray-forming disk and in the lowermost views showing the control disk and the spray-forming disk assembled together for use;

FIG. 5 comprises a set of three views each of each of the control disk and the spray-forming disk assembled together, showing them in the first flow state configuration (stream mode) on the left and in the second flow state configuration (spray mode) on the right;

FIG. 6 is a set of two views of the device fitted to the delivery/outlet end of a conventional kitchen sink mixer tap—in the left hand images the device is in its first flow state configuration (stream mode) and in the right hand images it is in the second flow state configuration (spray mode).

FIG. 7 is a set of two views of the device corresponding to FIG. 6 with the device in its second flow state configuration (spray mode) and showing the effect of increased water supply to the device from the tap;

FIG. 8 comprises a set of three views including a front elevation view of the control disk and the spray-forming disk assembled together, and sections therethrough along lines A1-A1 and A3-A3 to show the slanted nozzles and the location of the spring wire;

FIG. 9 comprises a set of three views including a front elevation view of the control disk and the spray-forming disk assembled together, a section along the line A2-A2 and a part cut-away exploded assembly view of the same;

FIG. 10 is an exploded general assembly diagram of a second preferred embodiment of the tap outlet flow adjustor having a control disk for selecting the flow state a spray forming disk, and a separate holding body the holding body being cylindrical and adapted to fit to the outlet/delivery end of a tap by an external screw thread thereon.

FIG. 11 is an exploded general assembly diagram, similar to FIG. 1 but of a third preferred embodiment of the tap outlet flow adjustor that has the spray-forming disk lowermost but differs from the first embodiment in that it is configured to mount to the tap end by the control disk and whereby the spray-forming disk may be de-mounted while the control disk remains in situ;

FIG. 12 comprises a set of views of the third embodiment's control disk showing its front and rear faces and details of the faces and with the spring clips mounted in place;

FIG. 13 comprises a further set of views of the third embodiment's control disk showing details of the rear face for mounting to the tap end;

FIG. 14 comprises a set of views of the third embodiment's spray-forming disk and showing details of its front and rear faces; and

FIG. 15 comprises a set of views of the third embodiment's control disk with the spring clips removed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, the first preferred embodiment of the tap outlet flow adjustor comprises two ‘disks’—a control disk 5 for selecting between first (stream-flow) and second (spray) flow states and a spray forming disk 4.

The control disk 5 is a substantially flat and substantially circular component that may be moulded of nylon or other tough plastics material or may be of a rust-proof metal or alloy. It has a short upstanding circumferential wall that has a radially outwardly projecting lip/rim. The control disk 5 has an array of four equi-angularly spaced open voids 24 spaced about its central axis (see central axle stub-accommodating aperture 25). It is through the voids 24 in control disk 5 that water passes in use. The voids 24 have the form of apertures through the floor of the disk 5 that are sectors of the circular plan shape of the disk 5. Each of the four voids 24 spans 45° of the circular floor area. The non-apertured sectors 23 of the disk floor between adjacent voids 24 are equally-sized 45° sectors and each acts as a barrier to water flow at that sector and can thus act as a means to selectively divert water flow.

The control disk 5 further has an operating lever 38 that projects downwardly (forwardly) and radially outwardly from the front face thereof (ie from the face that is outermost from the tap end) to allow the disk 5, once assembled to the spray-forming disk 4, to be turned about the axis 25 around the axle stub 39 of the spray forming disk 4.

The spray-forming disk 4 is in several respects similar to the control disk 5. The spray-forming disk 4 has an array of four 45° equi-angularly spaced open running voids 35. These are thus spaced about the central axis/axle stub 39 of the spray-forming disk 4 to match the shape, size and arrangement of the voids 24 of the control disk 5. Between the open running voids 35 of the spray-forming disk 4 are the spray-forming sectors 34 of the spray-forming disk 4, each of which has a plurality of perforations 34 b. The spray-forming disk 4 also has an upstanding circumferential wall 63 that is short but not as short as the corresponding wall of the control disk 5. The wall 63 has an external screw thread 65 formed on it whereby the spray-forming disk 4 is adapted to be able to readily de-mountably mount to the outlet/delivery end of a tap that has an internal screw thread at its outlet end. An elastomeric O-ring sealing member 3 is provided that fits in an annular groove 66 around the circumference of the spray-forming disk 4. This prevents any leakage from between the tap outlet end and the device when the device is fitted to a tap in use.

The control disk 5 nests into the rear of the spray-forming disk 4 within the upstanding circumferential wall 63 thereof. The control disk 5 is able to partially rotate about the axle stub 39 of the spray-forming disk 4 but is restricted in its turning by abutment of the lever 38 against end stop/limiting protrusions 70 on the outer/front face 71 of the spray-forming disk 4. These end stop/limiting protrusions 70 allow the control disk 5 to turn about axle stub 39 only between first radial orientation 69 and second radial orientation 68 that are 45° apart, corresponding to the width of the voids 24, so that at the first orientation the voids 24 of the control disk 5 align with the open running voids 35 of the spray-forming disk 4 to provide a stream or jet-like flow from the device, while at the second orientation the voids 24 of the control disk 5 align with the perforated floor sectors 34 of the spray-forming disk 4 and the open running voids 35 of the spray-forming disk 4 are closed off by the non-apertured sectors 23 of the control disk 5, thereby providing a spray flow from the device.

To help to keep the device in one state (ie either shower or flow state) and, for example, make the device less liable to being left inadvertently in an intermediate state whereby a user might accidentally spray himself or incur spillage, one or more wire springs 10 is provided in the control disk 5 to resiliently bias the device to the first or second state. The wire spring 10 is bent into an arched form that lies in a groove 27 in the surface of the control disk 5 as shown in FIG. 1 and the apex of the arched form of the wire spring 10 sits in a short angular recess/groove 36 in the circumference of the upper end 33 of the spray-forming disk's axle stub 39. The spray-forming disk's axle stub 39 extends up through the central aperture 25 in the control disk 5 and thus couples the control disk 5 and spray disk 4 together while allowing the relative rotation between the two. The combination of the spring 10 and groove 36 a/36 b forms a securing arrangement that demountably secures the assembled control disk 5 and spray disk 4 together.

A radius bend in the curve of the wire spring 10 increases its efficiency and flexibility. In the operation of the wire spring 10 the portion in the recess 36 will slip on the raised hump portion 36 a of the floor of the recess 36 (see upper diagram of FIG. 2) and in slipping to the respective side of the hump 36 b to relieve the tension in the wire spring (10) it will be biasing the control disk 5 substantially fully to one of the first and second states rather than letting it sit in any intermediate state. A partially angularly caved shape helps to allow the wire spring (10) to apply force on and rest on one of the flat faces 36 b of the recess 36.

The end stop/limiting protrusions 70 as illustrated are suitably demountable via a pin 76 at their upper face which fits into a slot 77 (see FIG. 2) in the underside/external face 71 of the spray-forming disk 4. The shape of the protrusions 70 is suitably a rounded rather than cuboidal form. Demountability of the end stops 70 can serve as a means to facilitate disassembly of this version of the device. The demountable end stop/limiting protrusions 70 when removed allow the lever 38 to be turned beyond the limits to disengage it from the spray-forming disk 4. The turning of the control disk 5 beyond the 45° point helps release the wire spring 10 which moves to surface 36 c and allows the ridge 32 to enter the broader recess 28 c of the control disk 5, whereupon the control disk 5 can be pushed from below through the voids 35 to demount from the axle stub 39.

As noted above, for disassembly, when the spray-forming disk 4 is turned more than 45 degrees the wire 10 will be brought on to the vertical surface 36 c of the axle stub and with no obstruction in this area 36 c the control 5 and spray-forming 4 disks can be then separated for maintenance. The top portion 33 of the axle stub 39 functions as a cap to retain the spring wire 10 from escaping while assembled.

The reverse of the disassembly process is followed for re-assembly. When re-installing the end stops 70 their cylindrical shape simplifies the process, avoiding mismatched orientations and inconsistent end stop-to-end stop spans.

As noted earlier, the spray-forming disk has in its spray-forming sectors a plurality of perforations 34 b. These perforations 34 b each extend into a respective nozzle 42 on the outer face of the spray-forming disk 4 and the passage of each perforation 34 b and through the nozzle 42 is of tapered form, each having a wider bore at their end adjacent the tap and narrowing towards their other end. The diameters of the perforation and nozzle 42 bores at each end and their positions and slant angles are such as to provide a desired relatively broad spray coverage area at a standard length from the nozzles. The arrangement of the nozzles separates the flow into a spray pattern. Raising the supply pressure to the device will widen the spray area and reducing water pressure will conversely reduce spread. To provide a broad spray coverage area each nozzle 42, and particularly each of the outermost nozzles 42 is inclined radially outwardly in the direction of flow. This inclination is suitably selected to reach the full width of a sink at maximum water flow rate. The nozzles help to maintain good delivered pressure in spray mode since the delivered water pressure from the spray will increase as its passes from the wider inner end of each nozzle 42 to the narrower outer end.

The system works effectively, adjusting with ease between spray and stream flow and operating reliably in each state, even if there is reduced water pressure/supply to the tap (see FIG. 7), whereas the prior art aerated devices need sustained high pressure water supply—especially those that mix the water with air.

The device may be partially self cleaning since the mutually facing major disk surfaces of the control and spray-forming disks 4, 5 may dislodge any lime-scale building up between them as they rotate over each other. Furthermore, the ease of demounting of the device from the tap and ease of disassembly of the disks 4, 5 of the device from each other enables the device to be thoroughly cleaned at regular intervals to maintain a long effective working life of the device.

As an improved extra (or alternative) relative rotation feature that may replace the axle stub, a ridge 32, preferably convex rounded, may be built on to a ledge of the circumferential wall 40 of the spray-forming disk 4 and serve to co-operate with/run up and down a channel 28 c (see FIG. 3). This engages into a partially closed round-shaped recess 28 a after the point 28 b.

In variants of the device, whereas the presently illustrated device has the four 45° void sectors 24 each separated by a 45° non-void sector 23 in the control disk 5 and with a corresponding pattern in the spray-forming disk 4, there could be a greater or lesser number of voids with correspondingly lesser or greater sector angle sizes. Furthermore, for ensuring a complete closure of the voids of the spray-forming disks, the non-void sectors 23 of the control disk 5 could be slightly greater in angular area than the void sectors 35 or perforated sectors 34 of the spray-forming disk 4 so that there is complete overlap of the edges of the latter and thus no leakage.

In a further variant the non-void sectors 23 in the control disk 5 may be formed slightly smaller than the perforated sectors 34 so that when the first state (stream flow) is adopted the non-void sectors 23 completely move fully onto the perforated sectors 34 fully covering the perforations and being fully away from the void sectors 35 of the spray-forming disk. When the second state (spray flow) is selected the non-void sectors 23 will overlie the void sectors 35 of the spray-forming disk 4, over-lapping the un-perforated edges of the perforated sectors 34 to not let any water pass through any part of the void sectors 35.

Suitably the spray-forming disk 4 upstanding circumferential wall 63 has its inner circumferential shelf 37, that the control disk 5 sits onto, lowered so that the outer lip/rim 21 of the control disk 5 is as close as possible to the floor of the spray-forming disk 4. This further facilitates operation of the raised, rounded (or not) rotation limiting ridge 32, if present, to co-operate with the corresponding recess 28 a-c on the bottom surface of the control disk 5.

Turning to FIG. 10, in the second embodiment of the invention, the device comprises a control disk for selecting the flow state, a spray forming disk, and a separate holding body. The holding body 4 is cylindrical and adapted to fit to the outlet/delivery end of a tap by an external screw thread 65 thereon. The construction and operation of the components is similar to that in the first embodiment, but the spray-forming disk is designed to be partly rotatable and has the operating lever extending from it, while the control disk is held immobile on the tap end by the holding body which prevents rotation of the control disk therewithin.

In the embodiments of the invention the securing effect of the spring 10 in holding the assembled disks 4, 5 together is augmented by the effect of the running water in use that also pushes the control disk 5 towards the spray-forming disk 4. The intimate arrangement of the mutually rotating disks 4, 5 helps to disrupt any build-up of lime-scale in use and the assembly of the device facilitates its disassembly for maintenance when cleaning is needed.

Referring now to FIGS. 11 to 15, the third preferred embodiment of the tap outlet flow adjustor is similar to the first embodiment of FIGS. 1 to 9. It also comprises two ‘disks’—a control disk 5 for selecting between first (stream-flow) and second (spray) flow states and a spray forming disk 4. Indeed, the reference numerals used with reference to the first embodiment of FIGS. 1 to 9 are conserved/used for the corresponding features in the third preferred embodiment of FIGS. 11 to 15.

The control disk 5, as shown in FIGS. 11, 12, 13 and 15, is a taller cylinder than that of the first embodiment and it is adapted to mount to the tap outlet/delivery end instead of the spray forming disk 4 doing so. The external screw thread 65 that threadedly engages with the tap outlet/delivery end is thus here on the exterior of the control disk 5 rather than on the exterior of the spray forming disk 4. The spray forming disk 4 is not screwed or otherwise mounted to the tap but rather it is fastened/clipped to the control disk 5 while the control disk 5 is secured to the tap. This arrangement facilitates demounting of the spray forming disk 4, which is the part that requires cleaning/maintenance the most, without necessitating demounting of the device as a whole from the tap.

In this embodiment the control disk 5 is shown as having an array of three equi-angularly spaced open voids 24 spaced about its central axis to correspond to three equi-angularly spaced void sectors 35 or perforated sectors 34 of the spray-forming disk 4. As noted earlier, however, the number of voids in the array may be three, four or more or less than that.

The selective de-mountability of the spray forming disk 4 from the tap-mounted control disk 5 part of the device is enabled by a modified version of the arched spring wires 10 from the first embodiment. Here the arched spring wires 10 are also each held in a groove/recess 27 in the rear/upper in use surface of the control disk 5 and the apex of the arch again clips into a short angular recess/groove 36 in the circumference of the upper end 33 of the spray-forming disk's axle stub 39. Again the spray-forming disk's axle stub 39 extends up through the central aperture 25 in the control disk 5 and thus couples the control disk 5 and spray disk 4 together while allowing the relative rotation between the two. The combination of the spring 10 and groove 36 thus again forms a securing arrangement that demountably secures the assembled control disk 5 and spray forming disk 4 together. However, the arched spring wires 10 in this third embodiment are suitably smaller and more robust, each fitting within a groove/recess 27 in the rear/upper in use surface of the control disk 5 that is arched and wholly within one of the non-void sectors 23 in the control disk 5 so that the arched spring wire 10 spans only a non-void sector 23 but not a void sector 24. Furthermore, the recess 36 is modified in shape so that in the operation of the wire spring 10 the portion in the recess 36 will not disengage therefrom merely by rotation. The spray-forming disk 4 must be pulled downwardly/away from the tap end to disengage it from the control disk 5 and hence demount it from the tap.

For the third embodiment, or indeed any of the embodiments, the preferred manner of fastening to the outlet/delivery end of a tap is by a screw threaded engagement. However, other means of fastening/clamping the device to the tap may be employed. In the third embodiment the control disk 5 may firstly be screw threadedly mounted to the outlet/delivery end of the tap and then the spray-forming disk 4 pushed upwardly/towards the tap end to engage the axle stub 39 of the spray-forming disk 4 into the control disk 5.

A chamfered or otherwise sloped/radially inwardly upwardly tapered perimeter 87 of the top end of the axle stub 39 of the spray-forming disk 4 facilitates the top of the axle stub 39 pushing past the apex of the arch or each arched spring wire 10 so that the compressed arched spring wires 10 pass over the full outer diameter surface 36 c of the top end of the axle stub 39 and then snap back out into the angular recess/groove 36 in the axle stub 39 firmly holding the axle stub 39 in place. The narrowed top end of the axle stub 39 is suitably of diameter substantially equal to the diameter of the circular central space between the apices/arches of the spring wires 10 in the circular central opening 25 of the control disk 5. When assembled, annular vertical wall 37 of the spray-forming disk 4 seats into annular channel 21 b of the control disk 5 which supports a smooth rotation between the disks 4, 5. The spring wire 10 in the central open area 25 of the control disk 5 holds the disks 4, 5 together when assembled and while they are turned to switch between the respective spray and stream running modes.

To remove the spray-forming disk 4 for maintenance the user simply turns the spray-forming disk 4 until the raised hump portion 36 a of the floor of the recess 36 of axle stub 39 coincides with the arch of the spring wire 10, forcing it outwardly to ride onto the full outer diameter surface 36 c of the top end of the axle stub 39 and pulls downwardly. The spray-forming disk 4 can only be removed when the raised hump portion 36 a of the floor of the recess 36 of axle stub 39 coincides with the arch of the spring wire 10. This allows the spray-forming disk 4 to securely rotate without de-mounting and only de-mount if pulled downwards at the designated release angular position as described.

To guide the user to the correct rotational position of the spray-forming disk 4 for de-mounting from the control disk 5, one or more indicia may be provided on the disks 4, 5. Suitably an indicium on the control disk 5 has a corresponding indicium on the spray-forming disk 4 that indicates when the spray-forming disk 4 is at the pull down position relative to the control disk 5.

In the spray-forming disk 4 of FIG. 14, rather than nozzles on the underside, the perforations 34 b of the spray-forming disk 4 may be provided with a respective funnel wall around each of the perforations on the top surface of the spray-forming disk 4 to funnel water down through the circular outlet 42 of the perforation 34 b. This increases the radially outwardly directed pressure in the spray mode. As can be further seen from FIG. 14, the funnel walls or partition walls between perforation 34 b taper towards their upper end and are shown as being square in plan at their upper end, forming a grid of cells each converging down towards a respective circular outlet 42 of the respective perforation 34 b. This configuration optimises the flow and pressure through the device in spray mode. The underside/outer face of the spray-forming disk 4 has a convex curvature so that it is slightly domed in shape, enhancing radially outward spread.

In this third embodiment, of the spray-forming disk 4 and control disk 5 one disk 4, 5 can be removed without the other being removed from the tap end. The lower/outermost disk will not, however, demount accidentally while just rotating. The lower/outermost disk will only demount when first turned to a designated angle and then pulled downwardly. In the preferred arrangement for this embodiment the control disk 5 may remain on the tap while allowing the spray-forming disk 4 to be separately demounted. This optimises efficiency since in this embodiment it is the spray-forming disk 4 that is the part most frequently in need of cleaning/maintenance. The control disk 5 need only occasionally be demounted from the tap end for infrequent maintenance and this helps longevity of the device. The O ring 3 (FIG. 11) assists in secure sealed mounting of the control disk 5 to the tap delivery end. Turning of the spray-forming disk 4 is facilitated by a knurled perimeter 86 to the annular flange 85 projecting from the circumference of the spray-forming disk 4

In all illustrated embodiments of the invention the output of water may be switched between a centralised stream flow of water and a more broadly spread spray of water simply by turning the spray-forming disk 4 and control disk 5 relative to each other. In most cases it is simply a matter of turning the lowermost/outermost disk clock-wise or counter-clockwise by a partial turn. Turning one way provides stream flow while turning back the other way provides spray flow. The flow is thus alternatively either spray or stream-running depending on whether the turn is clock-wise or counter-clockwise. 

What is claimed is:
 1. A selectable tap outlet flow adjustor for controlling water flow, the flow adjustor being adapted to be mounted or installed, mounted directly to the outlet/delivery end of a tap and comprising: a control disk for selecting the flow state comprising angularly spaced open voids spaced about an axis through which voids water passes when in use; and a spray forming disk, the spray forming disk also comprising angularly spaced open running voids spaced about an axis through which voids water may pass when in use but further comprising perforations in those parts of its body between the angularly spaced open voids through which perforations water may pass at a reduced spray rate when in use, the spray forming disk and control disk being axially rotatable with respect to each other whereby when one disk is rotated relative to the other so that the open running voids of the spray forming disk are aligned with the open voids in the control disk, water may pass through at a first flow rate and when one disk is rotated relative to the other so that the perforations in the spray forming disk are aligned with the open voids in the control disk, water may pass through at a second flow rate, less than the first flow rate and as a spray.
 2. A selectable tap outlet flow adjustor as claimed in claim 1, wherein the open voids of the control disk and the open running voids of the spray forming disk are sectors of those respective disks.
 3. A selectable tap outlet flow adjustor as claimed in claim 1, wherein the adjustor has a body mountable to the delivery end of a tap and which is a short cylinder in form.
 4. A selectable tap outlet flow adjustor as claimed in claim 1, wherein the adjustor is adapted to be inserted into the delivery end of a tap with an internal screw thread and has an external screw thread to be fastened to a tap end.
 5. A selectable tap outlet flow adjustor as claimed in claim 1, wherein the adjustor has a body mountable to the delivery end of a tap and the body and the spray forming disk are unitary/integrally formed or integrally assembled.
 6. A selectable tap outlet flow adjustor as claimed in claim 1, wherein the adjustor has a holding body mountable to the delivery end of a tap and the holding body and the spray forming disk are separate and the holding body holds the control disk in use so that the control disk does not rotate with respect to the holding body.
 7. A selectable tap outlet flow adjustor according to claim 1, wherein the spray forming disk or control disk comprises a turning lever, operable to rotate the disc and extending outside of the selectable tap outlet flow adjustor.
 8. A selectable tap outlet flow adjustor according to claim 1, wherein at least some of the perforations have their flow output directed/slanted laterally/radially outwardly so that the spray has a broadened spread.
 9. A selectable tap outlet flow adjustor as claimed in claim 8, wherein a passageway that a perforation forms is itself directed/slanted laterally/radially outwardly.
 10. A selectable tap outlet flow adjustor as claimed in claim 8, wherein a perforation forms a nozzle, or terminates at its external end in a nozzle, the nozzle having a bore narrowing in the direction of flow.
 11. A selectable tap outlet flow adjustor as claimed in claim 10, wherein the nozzle is directed/slanted laterally/radially outwardly.
 12. A selectable tap outlet flow adjustor according to claim 1, further comprising a resilient biasing spring to bias the selectable tap outlet flow adjustor to the first or second flow state.
 13. A selectable tap outlet flow adjustor as claimed in claim 1, wherein, by virtue of the stacked disk construction and intimacy of disks, the adjustor is so compact in form as to fit substantially wholly within the end of the tap in use.
 14. A selectable tap outlet flow adjustor as claimed in claim 1, wherein, by virtue of the intimate disk construction where the control disk rotates over the spray-forming disk, the adjustor is partially self-cleaning in use.
 15. A selectable tap outlet flow adjustor as claimed in claim 1 wherein a first of the spray forming disk and the control disk is mounted to the end of the tap and the second disk is demountable from the first without demounting the first from the end of the tap.
 16. A selectable tap outlet flow adjustor as claimed in claim 15, wherein the control disk mounts to the end of the tap and the spray forming disk mounts to the control disk and is demountable therefrom.
 17. A selectable tap outlet flow adjustor as claimed in claim 15, wherein the second disk will not demount from the first by turning alone.
 18. A selectable tap outlet flow adjustor as claimed in claim 17, wherein the second disk is demountable by turning to a designated radial orientation and pulling.
 19. A selectable tap outlet flow adjustor for controlling water flow, the flow adjustor being adapted to be mounted or installed, mounted directly to the outlet/delivery end of a tap and comprising: a control disk for selecting the flow state comprising open voids through which voids water passes when in use; and a spray forming disk, the spray forming disk also comprising open running voids through which voids water may pass when in use but further comprising perforations in those parts of its body between the open voids through which perforations water may pass at a reduced spray rate when in use, the spray forming disk and control disk being axially rotatable with respect to each other whereby when one disk is rotated relative to the other so that the open running voids of the spray forming disk are aligned with the open voids in the control disk, water may pass through at a first flow rate and when one disk is rotated relative to the other so that the perforations in the spray forming disk are aligned with the open voids in the control disk, water may pass through at a second flow rate, less than the first flow rate and as a spray wherein at least some of the perforations have their flow output directed/slanted laterally/radially outwardly so that the spray has a broadened spread.
 20. A selectable tap outlet flow adjustor for controlling water flow, the flow adjustor being adapted to be mounted or installed, mounted directly to the outlet/delivery end of a tap and comprising: a control disk for selecting the flow state comprising open voids through which voids water passes when in use; and a spray forming disk, the spray forming disk also comprising open running voids through which voids water may pass when in use but further comprising perforations in those parts of its body between the open voids through which perforations water may pass at a reduced spray rate when in use, the spray forming disk and control disk being axially rotatable with respect to each other whereby when one disk is rotated relative to the other so that the open running voids of the spray forming disk are aligned with the open voids in the control disk, water may pass through at a first flow rate and when one disk is rotated relative to the other so that the perforations in the spray forming disk are aligned with the open voids in the control disk, water may pass through at a second flow rate, less than the first flow rate and as a spray wherein a resilient biasing means is provided in the device to bias the device to the first or second flow state.
 21. (canceled)
 22. (canceled)
 23. A selectable tap outlet flow adjustor as claimed in claim 1, wherein turning of the spray-forming disk is facilitated by a grip surface at or around the circumference of the spray-forming disk.
 24. A selectable tap outlet flow adjustor as claimed in claim 1, wherein the perforations of the spray-forming disk each have a circular outlet and are each surrounded by a respective upstanding perimeter wall that forms a square or polygon to give a square or polygonal upper/inlet to the perforation that has a broader area than the circular outlet.
 25. A selectable tap outlet flow adjustor according to claim 1, wherein one or more spring clips or spring wires or other resiliently biased latch is provided that demountably clips/holds the control disk and spray-forming disk together.
 26. A selectable tap outlet flow adjustor according to claim 25, wherein each of the one or more spring clips or spring wires or other resiliently biased latch engages into a recess in an axle of the selectable tap outlet flow adjustor.
 27. A selectable tap outlet flow adjustor according to claim 25, wherein the one or more spring clips or spring wires or other resiliently biased latch also functions to bias the device to the first or second flow state.
 28. A selectable tap outlet flow adjustor as claimed in claim 1, wherein the perforations of the spray-forming disk are a plurality of through holes moulded extending through the disk. 